1. Field of the Invention
The present invention relates to a portable mobile communication terminal, and in particular to a communication terminal and an additional function module thereof.
2. Description of the Related Art
Recently, since a communication terminal, particularly, a portable mobile communication terminal is manufactured in a small size, it is difficult to add application hardware after a complete communication terminal is released to the market. Although a contact port may be provided in the communication terminal for connecting a small-sized memory card or an authentication/encryption card thereto, there is a spatial limit due to the small size of the communication terminal.
Such a characteristic of the communication terminal makes it difficult to connect an additional apparatus to the communication terminal when a user wants to add application hardware for a desired purpose. For example, the communication terminal must be connected with an external device through a wired port (e.g., a cable) or a wireless port (e.g., Bluetooth or IF port).
According to PCT publication No. WO2004/038943 A1, a battery module providing direct current power to a communication terminal through a power supply terminal has a specific application function installed therein. In addition, the communication terminal provides additional functions in a battery packet while communicating with the battery module through a communication unit. Although there may not be a need to purchase a new communication terminal in order to add a new function to the communication terminal unit, a user is required to continuously purchase battery modules in which a new application function is installed and must continuously replace the battery module whenever the user wants a different application function. That is, one battery module cannot provide a plurality of additional functions.